Step device for vehicle

ABSTRACT

A step device for a vehicle includes a movable step and a coupling member. The movable step includes a guide rail. The coupling member is configured to cause the movable step to move from a deployed position to a retracted position as a engaging part comes into sliding contact with a side wall of the guide rail that is located on an inner side in a vehicle width direction and, while pressing the side wall, moves inside the guide rail in a direction of closing a sliding door. The guide rail is configured such that a terminal end region on a closing side including a terminal end position at which the engaging part is located when the sliding door is fully closed constitutes a closing-side free running zone in which the engaging part does not press either of the side walls.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2019-164028 filed on Sep. 9, 2019, incorporated herein by reference in its entirety.

BACKGROUND 1. Technical Field

The present disclosure relates to a step device for a vehicle.

2. Description of Related Art

There are step devices for vehicles in which a movable step provided under a door opening is moved in a vehicle width direction in conjunction with opening and closing of a sliding door. For example, in the step device described in Japanese Patent Application Publication No. 2007-269086, a movable step is coupled to a sliding door through a guide member that is provided on a lower surface of the movable step and a coupling member that has a sliding member guided by the guide member. Thus, the movable step is moved to a deployed position on an outer side in a vehicle width direction in conjunction with the sliding door as the sliding door opens toward a vehicle rear side while shifting toward the outer side in the vehicle width direction, and is moved to a retracted position on an inner side in the vehicle width direction in conjunction with the sliding door as the sliding door closes toward a vehicle front side while shifting toward the inner side in the vehicle width direction.

SUMMARY

In a configuration in which a sliding door and a movable step are coupled together as described above, the movable step puts a load on the sliding door. As a result, the force required to open and close the sliding door increases. This is where there is still room for improvement.

The present disclosure provides a step device for a vehicle that can reduce the force required to open and close a sliding door.

A step device for a vehicle according to one aspect of the present disclosure includes a movable step that is supported under a door opening of the vehicle, and a coupling member that, in a state of being supported by a sliding door that moves in a front-rear direction of the vehicle with a shifting zone in a width direction of the vehicle, engages with the movable step to move the movable step in the vehicle width direction in conjunction with opening and closing of the sliding door. The movable step is provided with a guide rail extending in the front-rear direction of the vehicle, with an engaging part of the coupling member that moves integrally with the sliding door being disposed inside the guide rail. The coupling member is configured to cause the movable step to move from a retracted position to a deployed position as the engaging part comes into sliding contact with a side wall of the guide rail that is located on an outer side in the vehicle width direction and, while pressing the side wall, moves inside the guide rail in a direction of opening the sliding door. The coupling member is configured to cause the movable step to move from the deployed position to the retracted position as the engaging part comes into sliding contact with a side wall of the guide rail that is located on an inner side in the vehicle width direction and, while pressing the side wall, moves inside the guide rail in a direction of closing the sliding door. The guide rail is configured such that a terminal end region on a closing side including a terminal end position at which the engaging part is located when the sliding door is fully closed constitutes a closing-side free running zone in which the engaging part does not press either of the side walls.

Typically, a sliding door of a vehicle has a shifting zone in a vehicle width direction near its fully closed position. Opening a sliding door from the fully closed position requires a large force to move the sliding door that is in a stationary state, and fully closing a sliding door requires a force that allows the sliding door to squeeze a seal member, such as a weatherstrip. Therefore, an increase in the force required to open and close a sliding door caused by a load put on the sliding door by a movable step coupled thereto tends to be noticeable near the fully closed position.

In the above aspect, however, the movable step does not put a load on the sliding door while the engaging part of the coupling member moves through the terminal end region on the closing side as the closing-side free running zone set in the guide rail. Thus, the force required to open and close the sliding door can be reduced.

The present disclosure can reduce the force required to open and close a sliding door.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, advantages, and technical and industrial significance of exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

FIG. 1 is a perspective view of a vehicle showing a sliding door and a step device provided at a door opening;

FIG. 2 is a side view of the vehicle showing the sliding door and the step device provided at the door opening;

FIG. 3A is a plan view showing the sliding door that moves in a vehicle front-rear direction while shifting in a vehicle width direction, and the route of movement of the sliding door;

FIG. 3B is a plan view showing the sliding door that moves in the vehicle front-rear direction while shifting in the vehicle width direction, and the route of movement of the sliding door;

FIG. 4A is a plan view of the step device in a retracted position P1;

FIG. 4B is a plan view of the step device in a deployed position P2;

FIG. 5A is a plan view of the step device in the retracted position P1;

FIG. 5B is a plan view of the step device in the deployed position P2;

FIG. 6 is a sectional view of the step device;

FIG. 7 is a bottom view of the step device;

FIG. 8 is an exploded perspective view of a movable step;

FIG. 9 is a sectional view showing a guide roller unit as a coupling member that engages with a guide rail provided on the movable step;

FIG. 10 is an exploded perspective view of the guide roller unit;

FIG. 11 is a view illustrating free running zones set for the guide rail;

FIG. 12 is a view illustrating an action in a closing-side free running zone during opening of the sliding door;

FIG. 13 is a view illustrating an action in the closing-side free running zone during closing of the sliding door;

FIG. 14 is a view illustrating an action during movement in an opening-side free running zone;

FIG. 15 is an exploded perspective view of a sub-step;

FIG. 16A is a plan view of the sub-step;

FIG. 16B is a sectional view of the sub-step before assembly;

FIG. 16C is a sectional view of the sub-step in an assembled state;

FIG. 17A is a plan view of support arms that support the movable step in the retracted position P1;

FIG. 17B is a plan view of the support arms that support the movable step in the deployed position P2;

FIG. 18 is a perspective view of the movable step and support brackets that are coupled together through the support arms;

FIG. 19 is an exploded perspective view of the support arms and the support brackets;

FIG. 20 is a plan view around a first joint point of the support arm relative to the support bracket;

FIG. 21 is a sectional view around the first joint point of the support arm relative to the support bracket;

FIG. 22A is a side view of a pressure bearing member provided on the support bracket;

FIG. 22B is a bottom view of the pressure bearing member provided on the support bracket;

FIG. 23 is a bottom view around a second joint point of the support arm relative to the movable step;

FIG. 24 is a sectional view around the second joint point of the support arm relative to the movable step;

FIG. 25A is a bottom view of the pressure bearing member provided on a holding member that, together with the movable step, holds the support arm;

FIG. 25B is a side view of the pressure bearing member provided on the holding member that, together with the movable step, holds the support arm;

FIG. 26A is a bottom view of a resin cover constituting a part of the movable step;

FIG. 26B is a bottom view of a movable base constituting a part of the movable step;

FIG. 27 is a sectional view of the step device in a state where the movable step is in a retracted position;

FIG. 28 is a perspective view of a cover member, a seal member, and a retaining member;

FIG. 29A is a plan view of the cover member before assembly;

FIG. 29B is a plan view of the cover member disposed under the support arms and the support brackets in an assembled state;

FIG. 30 is a sectional view of the step device in the state where the movable step is in the retracted position;

FIG. 31 is a perspective view of the cover member with the seal member fixed at a leading end of a peripheral wall;

FIG. 32 is a perspective view of the cover member with the seal member fixed at the leading end of the peripheral wall;

FIG. 33 is a perspective view of the cover member with the seal member fixed at the leading end of the peripheral wall;

FIG. 34 is a sectional view of a vehicle front-side peripheral wall part that is provided at a front end portion of the cover member;

FIG. 35A is a side view of a guide roller unit in a coupled state;

FIG. 35B is a side view of the guide roller unit in an uncoupled state;

FIG. 36 is a view illustrating actions of inserting and removing the guide roller unit into and from a guide rail;

FIG. 37 is a bottom view of the guide rail showing a notch provided at a longitudinal end portion on a vehicle rear side;

FIG. 38 is a bottom view of the guide rail showing a notch provided at a corner of a curved portion;

FIG. 39A is an enlarged view of the retaining member provided on the bottom wall of the cover member in a used state;

FIG. 39B is an enlarged view of the retaining member provided on the bottom wall of the cover member in a retained state;

FIG. 40 is a view illustrating another example of movement of the movable step in the vehicle width direction in conjunction with opening and closing of the sliding door; and

FIG. 41 is a sectional view of a movable step and a sub-step showing another example of a stopper structure.

DETAILED DESCRIPTION OF EMBODIMENTS

One embodiment relating to a step device for a vehicle will be described below in accordance with the drawings. As shown in FIG. 1 , a vehicle 1 of this embodiment includes a sliding door 4 that can move in a vehicle front-rear direction (a left-right direction in FIG. 1 ) so as to open and close a door opening 3 provided in a side surface of a vehicle body 2.

Specifically, as shown in FIG. 2 , the vehicle 1 of the embodiment has a plurality of guide rails 10 that is provided on the side surface of the vehicle body 2 and extends in the vehicle front-rear direction. In particular, the vehicle 1 of the embodiment is provided with a lower rail 11 disposed at a lower edge of the door opening 3, a center rail 12 disposed on a rear side of the door opening 3, and an upper rail 13 disposed at an upper edge of the door opening 3. Further, each of these guide rails 10 has a guide roller unit 20 coupled thereto that can slide along an extension direction of the guide rail 10. In the vehicle 1 of the embodiment, the sliding door 4 is supported by the vehicle body 2 through the guide roller units 20 such that the sliding door 4 can open and close along the guide rails 10 extending in the vehicle front-rear direction.

As shown in FIG. 3A and FIG. 3B, each of the guide rails 10 of the embodiment has, at a longitudinal end portion 10 f on a vehicle front side, i.e., an end portion on a side where the sliding door 4 is fully closed, a curved portion 30 that curves toward an inner side in the vehicle width direction (the upper side in FIG. 3A and FIG. 3B) while extending from a vehicle rear side toward the vehicle front side. For the convenience of illustration, the lower rail 11 and a lower roller unit 21 are shown in FIG. 3A and the center rail 12 and a center roller unit 22 are shown in FIG. 3B, while the upper rail 13 and an upper roller unit 23 are not shown. The sliding door 4 of the embodiment opens and closes in the vehicle front-rear direction while shifting in the vehicle width direction in a state of being guided by the curved portions 30 provided in the guide rails 10.

When the sliding door 4 of the embodiment is in a fully closed position Pc, an outer surface 4 a thereof is substantially flush with a side surface 2 a of the vehicle body 2. When opening from the fully closed position Pc, the sliding door 4 moves toward the vehicle rear side while shifting toward the outer side in the vehicle width direction. A route of movement R of the sliding door 4 has, on the side of the fully closed position Pc, a width-direction shifting zone Rc in which the sliding door 4 shifts in the vehicle width direction. In FIG. 3A and FIG. 3B, the long dashed short dashed line represents the track of the opening and closing sliding door 4, particularly a front end portion thereof. Thus, in the vehicle 1 of the embodiment, the sliding door 4 does not interfere with the vehicle body 2 when opening and closing.

As shown in FIG. 2 , the vehicle 1 of the embodiment is provided with a power sliding door device 31 that opens and closes the sliding door 4 using a motor 31 m as a driving source. An occupant of the vehicle 1 can open and close the sliding door 4 not only by manual operation but also by operating a door handle (not shown), an operation switch provided inside a vehicle cabin, or a portable device. The power sliding door device 31 monitors changes in driving power required to open and close the sliding door 4, i.e., a force required to open and close the sliding door 4, based on rotation of the motor 31 m, an amount of current applied thereto, etc. Thus, the power sliding door device 31 functions as a catching detection device 32 that detects whether any object is caught in the sliding door 4.

In particular, the catching detection device 32 of the embodiment determines that an object is caught in the sliding door 4 when, for example, the amount of current to the motor 31 m increases beyond a predetermined threshold value while the sliding door 4 is driven to open or close. To release an object caught in the sliding door 4 or prevent the sliding door 4 from catching an object, the power sliding door device 31 of the embodiment executes driving control involving, for example, driving the sliding door 4, which is being driven to close, reversely in an opening direction or stopping the sliding door 4 being driven to open.

As shown in FIG. 1 and FIG. 2 , the vehicle 1 of the embodiment is provided with a step device 41 that deploys a step member 40 serving as a step under the door opening 3 to be used by an occupant who gets in or out of the vehicle 1.

Specifically, as shown in FIG. 4A, FIG. 4B, FIG. 5A, FIG. 5B, and FIG. 6 , the step device 41 of the embodiment includes a movable step 42 that is supported under the door opening 3 in a state of being movable in the vehicle width direction, and a sub-step 43 that is disposed under the door opening 3, along with the movable step 42, in a state of being fixed to the vehicle body 2. The vehicle width direction corresponds to an up-down direction in FIG. 4A, FIG. 4B, FIG. 5A, and FIG. 5B and a left-right direction in FIG. 6 .

In particular, as shown in FIG. 4A to FIG. 7 , the step device 41 of the embodiment includes a plurality of support arms 44 that is turnably coupled to both the vehicle body 2 and the movable step 42. By being supported by the support arms 44, the movable step 42 of the embodiment moves under the sub-step 43 in the vehicle width direction while maintaining a substantially horizontal posture.

More specifically, the step device 41 of the embodiment includes a plurality of support brackets 45 that is fixed to a lower surface 2 b of the vehicle body 2. The support arms 44 of the embodiment are coupled to the vehicle body 2 through the support brackets 45. In the step device 41 of the embodiment, each support arm 44 turns in a substantially horizontal direction around, as a fulcrum, a first pivot-joint point M1 relative to the vehicle body 2 that is formed by this coupling.

As shown in FIG. 6 to FIG. 8 , the movable step 42 of the embodiment includes a substantially flat-plate-shaped movable base 47 that has coupling portions 46 for the respective support arms 44, and a resin cover 48 that is fixed to the movable base 47 in a state of covering an upper surface 47 a of the movable base 47. In the movable step 42 of the embodiment, an upper surface 48 a of the resin cover 48 constitutes a step surface S1 on which a user places his or her foot. The coupling portions 46 for the respective support arms 44 are formed as insertion holes 49 extending through the movable base 47 in the up-down direction. Thus, in the step device 41 of the embodiment, each support arm 44 turns relatively to the movable step 42 around, as a fulcrum, a second pivot-joint point M2 that is formed using the coupling portion 46, while maintaining a substantially horizontal posture of the movable step 42.

In the movable step 42 of the embodiment, the movable base 47 is formed using metal. The upper surface 48 a of the resin cover 48 has depressions and protrusions to prevent slipping. Thus, the step device 41 of the embodiment allows an occupant having placed his or her foot on the movable step 42 to safely step onto the step surface S1.

As shown in FIG. 4A to FIG. 9 , the movable step 42 of the embodiment includes a guide rail 50 that is provided on a lower surface 42 b thereof and extends in a longitudinal direction. The step device 41 of the embodiment includes a guide roller unit 52 as a coupling member that, in a state of being supported by the sliding door 4, engages with the guide rail 50 of the movable step 42.

As shown in FIG. 6 to FIG. 8 , the guide rail 50 of the embodiment is formed by fixing, to the movable base 47 constituting the lower surface 42 b of the movable step 42, rail members 53, 54 that extend in the longitudinal direction of the movable base 47. In particular, the movable base 47 of the embodiment includes a peripheral wall 55 that is formed by folding down a peripheral edge portion of the movable base 47 on the outer side in the vehicle width direction toward the side of the lower surface 47 b and extends in the longitudinal direction. The rail members 53, 54 are integrally fixed to the lower surface 47 b of the movable base 47 so as to be parallel to the peripheral wall 55.

As shown in FIG. 6 and FIG. 9 , in the guide rail 50 of the embodiment, the peripheral wall 55 of the movable base 47 constitutes a side wall 57 on the outer side in the vehicle width direction, and the rail members 53, 54 facing the peripheral wall 55 in the vehicle width direction constitute a side wall 58 on the inner side in the vehicle width direction. The side wall 58 on the inner side in the vehicle width direction is provided with a fall prevention flange 59 that is formed by bending a lower end portion of the side wall 58 so as to extend toward the side wall 57 on the outer side in the vehicle width direction. In the step device 41 of the embodiment, the fall prevention flange 59 is provided in the rail member 53 constituting a part of the side wall 58 (see FIG. 8 ). The guide roller unit 52 of the embodiment includes a guide roller 60 that is disposed between side walls 57, 58 of the guide rail 50 facing each other.

In particular, as shown in FIG. 6 , FIG. 9 , and FIG. 10 , the guide roller unit 52 of the embodiment includes a fixed member 61 that is fixed to the sliding door 4 in a state of extending in the up-down direction, and an arm member 62 that extends toward the inner side in the vehicle width direction in a state of being coupled to a lower end of the fixed member 61. A support shaft 60 x extending in the up-down direction is provided at a leading end of the arm member 62. The support shaft 60 x of the guide roller unit 52 of the embodiment rotatably supports the guide roller 60.

The guide roller unit 52 of the embodiment moves integrally with the sliding door 4 based on opening and closing of the sliding door 4. The guide roller 60 disposed inside the guide rail 50 also moves in the vehicle front-rear direction according to the direction of movement of the sliding door 4. In the guide rail 50 of the embodiment, the fall prevention flange 59 provided at the lower end of the side wall 58 prevents the guide roller 60 located between the side walls 57, 58 from coming off. The guide roller unit 52 of the embodiment causes the movable step 42 provided with the guide rail 50 to move in the vehicle width direction as the guide roller 60 comes into sliding contact with and presses the side wall 57 of the guide rail 50 located on the outer side in the vehicle width direction or the side wall 58 of the guide rail 50 located on the inner side in the vehicle width direction.

In particular, the guide roller unit 52 of the embodiment causes the movable step 42 to move toward the outer side in the vehicle width direction as the guide roller 60 comes into sliding contact with the side wall 57 of the guide rail 50 located on the outer side in the vehicle width direction and, while pressing the side wall 57, moves inside the guide rail 50 in a direction toward the vehicle rear side that is the opening direction of the sliding door 4. The guide roller unit 52 causes the movable step 42 to move toward the inner side in the vehicle width direction as the guide roller 60 comes into sliding contact with the side wall 58 of the guide rail 50 located on the inner side in the vehicle width direction and, while pressing the side wall 58, moves inside the guide rail 50 in a direction toward the vehicle front side that is the closing direction of the sliding door 4. Thus, in the step device 41 of the embodiment, the movable step 42 is moved from a retracted position P1 to a deployed position P2 in conjunction with opening of the sliding door 4, and is moved from the deployed position P2 to the retracted position P1 in conjunction with closing of the sliding door 4 (see FIG. 4A to FIG. 5B).

More specifically, as shown in FIG. 7 and FIG. 11 , the guide rail 50 of the embodiment includes, at a longitudinal end portion 50 f on the vehicle front side, i.e., an end portion on the side where the sliding door 4 is fully closed, a curved portion 70 that curves toward the inner side in the vehicle width direction while extending from the vehicle rear side toward the vehicle front side, like the curved portion 30 provided in each guide rail 10 of the sliding door 4. The inner side in the vehicle width direction corresponds to the lower side in FIG. 7 and the upper side in FIG. 11 . Thus, in the step device 41 of the embodiment, the movable step 42 can be gently moved in the vehicle width direction as the guide roller 60 moves smoothly inside the guide rail 50 based on opening or closing of the sliding door 4.

Free Running Zones

Next, free running zones set for the guide rail 50 of the embodiment will be described. As shown in FIG. 11 , the guide rail 50 of the embodiment has two free running zones, one near the longitudinal end portion 50 f on the vehicle front side and the other on the vehicle rear side of the curved portion 70. In these free running zones, the guide roller 60 serving as an engaging part of the coupling member that moves integrally with the sliding door 4 does not press the side walls 57, 58 located on both sides of the guide roller 60 in the vehicle width direction. In particular, in the guide rail 50 of the embodiment, a terminal end region Lc on a closing side including a terminal end position Xc at which the guide roller 60 is located when the sliding door 4 is fully closed constitutes a closing-side free running zone ac. In the guide rail 50 of the embodiment, a moving region Lo on an opening side from a moving position X2 at which the guide roller 60 is located when the movable step 42 reaches the deployed position P2 constitutes an opening-side free running zone αo.

In the step device 41 of the embodiment, when the guide roller 60 moves in an engaging zone β located between the closing-side free running zone ac and the opening-side free running zone αo, the movable step 42 moves in the vehicle width direction in conjunction with opening and closing of the sliding door 4. Thus, the movable step 42 of the embodiment reaches the deployed position P2 from the retracted position P1 by an amount of shift W2 in the vehicle width direction that is smaller than an amount of shift W1 in the vehicle width direction that the sliding door 4 undergoes while opening or closing (W1>W2).

Specifically, as shown in FIG. 9 , in the guide rail 50 of the embodiment, the interval between the side walls 57, 58 facing each other in the vehicle width direction, i.e., a rail width Dw, is set to a value larger than a diameter Dr of the guide roller 60 (Dw>Dr). The closing-side free running zone ac of the embodiment constitutes a non-sliding-contact zone γ in which the guide roller 60 moving in the closing-side free running zone ac in the vehicle front-rear direction moves inside the guide rail 50 in the vehicle width direction, while shifting in a rail width direction without coming into sliding contact with the side walls 57, 58.

More specifically, as shown in FIG. 12 and FIG. 13 , in the closing-side free running zone αc, a gradient of change θ1 of the side wall 57 located on the outer side of the guide roller 60 in the vehicle width direction is set to be smaller than a gradient of change θr set for a track of movement Qr of the guide roller 60 that moves inside the guide rail 50 in the vehicle front-rear direction while moving in the vehicle width direction (θr>θ1). The lower side and the left side in FIG. 12 and FIG. 13 correspond to the outer side in the vehicle width direction and the vehicle front side, respectively. A gradient of change θ2 of the side wall 58 located on the inner side of the guide roller 60 in the vehicle width direction is set to be larger than the gradient of change θr set for the track of movement Qr of the guide roller 60 (θr<θ2).

Thus, as shown in FIG. 12 , in the guide rail 50 of the embodiment, the closing-side free running zone αc as the non-sliding-contact zone γ constitutes a zone in which, when the sliding door 4 opens, the guide roller 60 moving inside the guide rail 50 toward the vehicle rear side shifts in the rail width direction so as to be gradually closer to the side wall 57 located on the outer side of the guide roller 60 in the vehicle width direction. Thus, in the guide rail 50 of the embodiment, the guide roller 60 having passed through the closing-side free running zone αc comes quickly into sliding contact with the side wall 57 located on the outer side of the guide roller 60 in the vehicle width direction and presses the side wall 57.

Further, as shown in FIG. 13 , the closing-side free running zone αc as the non-sliding-contact zone γ constitutes a zone in which, when the sliding door 4 closes, the guide roller 60 moving inside the guide rail 50 toward the vehicle front side shifts in the rail width direction so as to be gradually away from the side wall 58 located on the inner side in the vehicle width direction. Thus, in the guide rail 50 of the embodiment, the guide roller 60 having entered the closing-side free running zone αc from the engaging zone β is quickly separated from the side wall 58 located on the inner side of the guide roller 60 in the vehicle width direction.

As shown in FIG. 11 , in the step device 41 of the embodiment, a moving position X1 of the guide roller 60 at the border between the closing-side free running zone αc and the engaging zone β corresponds to the retracted position P1 of the movable step 42. In the step device 41 of the embodiment, when the sliding door 4 opens, the movable step 42 reaches the deployed position P2 at the same time as shift of the sliding door 4 toward the outer side in the vehicle width direction is completed. In the step device 41 of the embodiment, as described above, the moving region Lo on the opening side from the moving position X2 at which the guide roller 60 is located when the movable step 42 reaches the deployed position P2 is set as the opening-side free running zone αo, so that the movable step 42 deployed under the door opening 3 does not put a load on the sliding door 4.

In particular, as shown in FIG. 11 and FIG. 14 , in the vehicle 1 of the embodiment, when shift of the sliding door 4 in the vehicle width direction is completed, the guide roller 60 that moves integrally with the sliding door 4 moves in the vehicle front-rear direction, substantially in a straight line. Based on this movement, a vehicle rear-side part of the guide rail 50 of the embodiment corresponding to the moving region Lo on the opening side extends in the vehicle front-rear direction, substantially in a straight line. Thus, in the step device 41 of the embodiment, a parallel zone E in which the side walls 57, 58 of the guide rail 50 extend parallel to the track of movement Qr of the guide roller 60 is formed, and the moving region Lo on the opening side constitutes the opening-side free running zone αo.

Sub-Step

Next, the configuration of the sub-step 43 in the step device 41 of the embodiment will be described.

As shown in FIG. 6 , FIG. 15 , and FIG. 16A to FIG. 16C, in the step device 41 of the embodiment, the sub-step 43 disposed under the door opening 3 along with the movable step 42 includes a base part 71 that is located above the movable step 42 and fixed to the side surface 2 a of the vehicle body 2 and a step part 72 that is coupled to the base part 71 so as to be turnable in the up-down direction.

In the step device 41 of the embodiment, the base part 71 and the step part 72 are coupled together through coupling shafts 73 that extend in a longitudinal direction of these parts. The base part 71 and the step part 72 are formed respectively by laying, on base members 75, 76 that have fitting portions 75 x, 76 x for the coupling shafts 73, resin covers 77, 78 that constitute decorative surfaces 71 s, 72 s of these base members 75, 76. In the sub-step 43 of the embodiment, the base part 71 is fixed to the side surface 2 a of the vehicle body 2 in such a position that the step part 72 that shifts in the up-down direction by turning around the coupling shafts 73 comes into sliding contact with an upper surface 42 a, i.e., the step surface S1, of the movable step 42 disposed under the sub-step 43.

In particular, the sub-step 43 of the embodiment has a structure in which a part of the resin cover 78 protrudes toward the side of a lower surface 72 b at a leading end portion of the step part 72. In the step device 41 of the embodiment, a projection 79 thus formed comes into sliding contact with the upper surface 42 a of the movable step 42.

Specifically, as shown in FIG. 4A to FIG. 6 , the movable step 42 of the embodiment moves under the sub-step 43 toward the outer side in the vehicle width direction and is thereby disposed in the deployed position P2 in which the movable step 42 protrudes from the sub-step 43 toward the outer side in the vehicle width direction. Also when the movable step 42 is in the deployed position P2, the sub-step 43 of the embodiment maintains the state where the step part 72 is in sliding contact with the upper surface 42 a. The sub-step 43 has an overlapping region η that covers an upper side of the movable step 42 in the state where the movable step 42 is disposed in the deployed position P2. Thus, in the sub-step 43 of the embodiment, the decorative surface 72 s of the step part 72 forms a step surface S2 that is integral with the step surface S1 of the movable step 42.

In the step device 41 of the embodiment, the resin cover 78 constituting the step surface S2 of the step part 72 of the sub-step 43 has depressions and protrusions to prevent slipping, like the step surface S1 of the movable step 42. Thus, the step device 41 of the embodiment allows an occupant who has placed his or her foot on the sub-step 43 to safely step onto the step surface S2.

Further, the sub-step 43 of the embodiment transfers a load applied to the step surface S2 to the movable step 42 as the step part 72 turns. In other words, in the step device 41 of the embodiment, a load applied to the sub-step 43 is passed on to the movable step 42. Thus, the load bearing capacity required of the sub-step 43 is reduced, which allows for reductions in the weight and manufacturing cost of the step device 41 of the embodiment.

In the step device 41 of the embodiment, a plurality of ridges 80 extending in the vehicle width direction is provided on the upper surface 42 a of the movable step 42 with which the sub-step 43 comes into sliding contact. Further, in the sub-step 43 of the embodiment, the projection 79 provided at the leading end portion of the step part 72 comes into sliding contact with the ridges 80. Thus, in the step device 41 of the embodiment, the area of contact between the step part 72 of the sub-step 43 and the movable step 42 is reduced to thereby reduce the sliding resistance to the movable step 42 moving in the vehicle width direction.

Support Structure of Movable Step

Next, the structure of supporting the movable step 42 in the step device 41 of the embodiment will be described.

As shown in FIG. 17A, FIG. 17B, FIG. 18 , and FIG. 19 , the step device 41 of the embodiment includes, as the support arms 44 of the movable step 42, two main arms 81 that are disposed apart from each other in the vehicle front-rear direction and a sub-arm 82 that is disposed between the main arms 81. In the step device 41 of the embodiment, the sub-arm 82 is formed by turnably coupling together a base end-side arm 83 coupled to the vehicle body 2 and a leading end-side arm 84 coupled to the movable step 42. The sub-arm 82 of the embodiment has a joint M3 at which the sub-arm 82 can be bent. The main arms 81 are not provided with the joint M3. The step device 41 of the embodiment includes, as the support brackets 45, a front bracket 45 f that couples a front main arm 81 f and the sub-arm 82 to the vehicle body 2 and a rear bracket 45 r that couples a rear main arm 81 r to the vehicle body 2.

Specifically, as shown in FIG. 6 and FIG. 19 to FIG. 21 , each support bracket 45 of the embodiment includes a bracket main body 85 that is fixed to the lower surface 2 b of the vehicle body 2, and a holding member 86 that, together with the bracket main body 85, holds a base end part 44 b of the support arm 44. In particular, the holding member 86 of the embodiment is disposed above the bracket main body 85, in such a position that the base end part 44 b of the support arm 44 is held between the holding member 86 and the bracket main body 85. In the step device 41 of the embodiment, a shaft member 90 is inserted into insertion holes 87, 88 formed respectively in the bracket main body 85 and the holding member 86 and an insertion hole 89 formed in the base end part 44 b of the support arm 44. In the step device 41 of the embodiment, the shaft member 90 is clinched, and thus the support bracket 45 forms the first pivot-joint point M1 of the support arm 44 relative to the vehicle body 2.

As shown in FIG. 19 , in the step device 41 of the embodiment, pluralities of fastening holes 85 x, 86 x are formed in the bracket main body 85 and the holding member 86, respectively. The fastening holes 85 x, 86 x are used to fasten the bracket main body 85 and the holding member 86 of each support bracket 45 of the embodiment integrally and simultaneously to the lower surface 2 b of the vehicle body 2.

FIG. 20 and FIG. 21 show the structure of supporting the front main arm 81 f by a bracket main body 85 f and a holding member 86 f of a front bracket 45 f. The structure of supporting the sub-arm 82 by the front bracket 45 f, particularly the structure of holding the base end-side arm 83 between the bracket main body 85 f and the holding member 86 f, is the same. Further, the structure of supporting the rear main arm 81 r by a bracket main body 85 r and a holding member 86 r of a rear bracket 45 r is also the same as the support structure of the front bracket 45 f For the convenience of illustration, therefore, an enlarged view and a sectional view of the support structures for the sub-arm 82 and the rear main arm 81 r are omitted.

As shown in FIG. 6 and FIG. 17A to FIG. 19 , in the step device 41 of the embodiment, the leading end part 44 a of each support arm 44 is disposed on the lower surface 47 b of the movable base 47 constituting a part of the movable step 42. The leading end part 44 a of each support arm 44 is provided with an insertion hole 91 similar to the insertion hole 89 formed in the base end part 44 b. In the step device 41 of the embodiment, a shaft member 92 is inserted into the insertion hole 91 and the insertion hole 49 of the movable base 47 constituting the coupling portion 46 on the side of the movable step 42. In the step device 41 of the embodiment, the shaft member 92 is clinched, and thus a second pivot-joint point M2 of the support arm 44 relative to the movable step 42 is formed.

As shown in FIG. 19 , in the step device 41 of the embodiment, the base end-side arm 83 constituting a part of the sub-arm 82 has an insertion hole 93, similar to the insertion hole 89 constituting the first pivot-joint point M1 relative to the vehicle body 2, formed at an end portion on the opposite side from the side where the insertion hole 89 is formed. Further, the leading end-side arm 84 has an insertion hole 94, similar to the insertion hole 91 constituting the second pivot-joint point M2 relative to the movable step 42, formed at an end portion on the opposite side from the side where the insertion hole 91 is formed. In the step device 41 of the embodiment, a shaft member 95 is inserted into the insertion holes 93, 94. In the step device 41 of the embodiment, the shaft member 95 is clinched to form the joint M3 of the bendable sub-arm 82.

As shown in FIG. 17A and FIG. 17B, in the step device 41 of the embodiment, when the movable step 42 is in the retracted position P1, each support arm 44 is disposed such that the base end part 44 b thereof extends from the first pivot-joint point M1 relative to the vehicle body 2 toward the vehicle front side. As the movable step 42 moves toward the outer side in the vehicle width direction in conjunction with opening of the sliding door 4, each support arm 44 turns in a counterclockwise direction in FIG. 17A and FIG. 17B around the first pivot-joint point M1 as a fulcrum, and as the movable step 42 moves toward the inner side in the vehicle width direction, each support arm 44 turns in a clockwise direction in FIG. 17A and FIG. 17B. Meanwhile, the base end-side arm 83 and the leading end-side arm 84 of the sub-arm 82 turn relatively to each other around the joint M3 so as to expand or contract the chevron-like bent shape. Thus, in the step device 41 of the embodiment, the second pivot-joint points M2 of the support arms 44 relative to the movable step 42 move in the vehicle front-rear direction while shifting in the vehicle width direction, which allows the movable step 42 to deploy and retract smoothly in conjunction with opening and closing of the sliding door 4 while being stably supported.

As shown in FIG. 6 , the step device 41 of the embodiment includes a plurality of pressure bearing members 100 that is provided under the support arms 44, each between the first pivot-joint point M1 relative to the vehicle body 2 and the second pivot-joint point M2 relative to the movable step 42, so as to come into sliding contact with the support arm 44 and bear the load thereof.

Specifically, as shown in FIG. 19 to FIG. 21 , the step device 41 of the embodiment includes pressure bearing members 101 that are each fixed to the bracket main body 85 of the support bracket 45 so as to come into sliding contact with the base end part 44 b of the support arm 44 supported by the support bracket 45. In the step device 41 of the embodiment, the pressure bearing members 101 are provided so as to correspond to the respective support arms 44, namely the front main arm 81 f and the sub-arm 82 supported by the front bracket 45 f and the rear main arm 81 r supported by the rear bracket 45 r.

In the step device 41 of the embodiment, the pressure bearing members 101 have substantially the same shape and pressure bearing structure. For the convenience of illustration, therefore, an enlarged view and a sectional view of only the pressure bearing member 101 that is provided on the front bracket 45 f so as to correspond to the front main arm 81 f are shown in FIG. 20 and FIG. 21 .

In particular, as shown in FIG. 22A and FIG. 22B, in the step device 41 of the embodiment, each pressure bearing member 101 has a form of a substantially arc-shaped flat plate. Each pressure bearing member 101 has, on a back surface 101 b thereof, a pair of protruding fitting projections 102. As the fitting projections 102 are fitted into mounting holes 103 (see FIG. 19 ) on the side of the bracket main body 85, the pressure bearing member 101 is fixed to the bracket main body 85 under the support arm 44. Thus, as shown in FIG. 21 , a front surface 101 a of each pressure bearing member 101 of the embodiment forms a sliding contact surface 101 s that comes into sliding contact with the base end part 44 b of the support arm 44 located above the pressure bearing member 101.

More specifically, as shown in FIG. 20 , each pressure bearing member 101 is disposed on a radially outer side of the first pivot-joint point M1 in such a state that the arc shape of the pressure bearing member 101 extends in a circumferential direction around the first pivot-joint point M1. Thus, in the step device 41 of the embodiment, each pressure bearing member 101 has the sliding contact surface 101 s extending in a direction intersecting the corresponding support arm 44.

As shown in FIG. 19 , FIG. 23 , and FIG. 24 , in the step device 41 of the embodiment, the movable step 42 is provided with a plurality of holding members 110 that is each fixed to the movable base 47 so as to, together with the lower surface 47 b of the movable base 47, hold the leading end part 44 a of the support arm 44 at the coupling portion 46 for the support arm 44 provided in the movable base 47. The step device 41 of the embodiment includes a plurality of pressure bearing members 111 that is each provided for the holding member 110 so as to come into sliding contact with the leading end part 44 a of the support arm 44 held by the holding member 110.

In particular, as shown in FIG. 17A, FIG. 17B, and FIG. 18 , the movable step 42 of the embodiment is provided with a pair of front and rear holding members 110 that, together with the lower surface 47 b of the movable base 47, hold the pair of front and rear main arms 81 that support the movable step 42 toward the upper side. The step device 41 of the embodiment includes a pair of pressure bearing members 111 provided one for each holding member 110.

In the step device 41 of the embodiment, the holding members 110 have the same shape and holding structure. For the convenience of illustration, therefore, an enlarged view and a sectional view of only the holding member 110 that corresponds to the rear main arm 81 r are shown in FIG. 23 and FIG. 24 .

Specifically, as shown in FIG. 19 , FIG. 23 , and FIG. 24 , the holding member 110 of the embodiment has a form of a curved plate with a substantially J-shaped cross-section, and includes a fixed part 112 that is fixed to the movable base 47 and a holding part 113 that extends substantially parallel to the fixed part 112. The holding member 110 has an insertion hole 114 extending through the holding part 113. In the step device 41 of the embodiment, the shaft member 92 constituting the second pivot-joint point M2 of the support arm 44 relative to the movable step 42 is inserted into the insertion hole 91 provided in the leading end part 44 a of the support arm 44 and the insertion hole 49 provided in the movable base 47 via the insertion hole 114. Thus, each holding member 110 of the embodiment holds the leading end part 44 a of the support arm 44 between the holding part 113 and the lower surface 47 b of the movable base 47 at the coupling portion 46 of the movable base 47.

In the step device 41 of the embodiment, the holding member 110 is fixed to the movable step 42 as the fixed part 112 is welded to the upper surface 47 a of the movable base 47. The holding part 113 of the holding member 110 is disposed on the side of the lower surface 47 b of the movable base 47 so as to surround a peripheral edge portion of the movable base 47. Thus, in the step device 41 of the embodiment, the force with which the support arms 44 support the movable step 42, particularly the force with which the main arms 81 provided with the holding members 110 are supported is enhanced for the second pivot-joint point M2 relative to the movable step 42.

As shown in FIG. 25A and FIG. 25B, each pressure bearing member 111 of the embodiment has a form of a substantially rectangular flat plate with a bent portion 111 x at one end. The pressure bearing member 111 has, on a back surface 111 b thereof, a protruding fitting projection 115. As the fitting projection 115 is fitted into a mounting hole 116 provided in the holding part 113 of the holding member 110 (see FIG. 19 ), the pressure bearing member 111 is fixed to the holding member 110 under the support arm 44. Thus, as shown in FIG. 24 , the front surface 111 a of the pressure bearing member 111 of the embodiment forms a sliding contact surface 111 s that comes into sliding contact with the leading end part 44 a of the support arm 44 located on the upper side of the pressure bearing member 111.

More specifically, as shown in FIG. 19 and FIG. 23 , each main arm 81 of the embodiment has a substantially fan-shaped flat plate part 117 at a part with which the pressure bearing member 111 comes into sliding contact. Thus, in the step device 41 of the embodiment, the area of contact between each main arm 81 and the pressure bearing member 111 is increased to thereby enhance the force with which the main arm 81 supports the movable step 42.

In the step device 41 of the embodiment, the pressure bearing members 100, namely, the pressure bearing members 101 on the side of the first pivot-joint points M1 provided on the support brackets 45 and the pressure bearing members 111 on the side of the second pivot-joint points M2 provided on the holding members 110, are each made of a resin having a shock absorbing property and a self-lubricating property. Examples of a resin material having these properties include polyacetal (POM). Thus, in the step device 41 of the embodiment, the support arms 44 can turn smoothly and, at the same time, occurrence of sliding noise thereof is reduced.

As shown in FIG. 26A, FIG. 26B, and FIG. 27 , in the step device 41 of the embodiment, the lower surface 42 b of the movable step 42 is provided with a plurality of ridges 118 that extends in directions intersecting the support arms 44 located under the movable step 42 and comes into sliding contact with the support arms 44.

As shown in FIG. 7 , the movable step 42 of the embodiment includes three ridges 118 corresponding to the front main arm 81 f, the sub-arm 82, and the rear main arm 81 r. The ridges 118 extend in a longitudinal direction of the movable step 42 that extends in the vehicle front-rear direction.

As shown in FIG. 26A, FIG. 26B, and FIG. 27 , in the movable step 42 of the embodiment, the ridges 118 are provided on the lower surface 48 b of the resin cover 48. The movable base 47 has elongated holes 119 at positions under the respective ridges 118. In the movable step 42 of the embodiment, the ridges 118 inserted into the respective holes 119 protrude toward the lower surface 47 b of the movable base 47 constituting the lower surface 42 b of the movable step 42.

In the movable step 42 of the embodiment, the ridges 118 come into sliding contact with the support arms 44 located under the ridges 118, so that the support arms 44 can stably support the load of the movable step 42. In the step device 41 of the embodiment, the ridges 118 extend in directions intersecting the support arms 44, which reduces the area of contact between each ridge 118 and the corresponding support arm 44. Thus, in the movable step 42 of the embodiment, the support arms 44 can turn smoothly and, at the same time, occurrence of sliding noise thereof is reduced.

As shown in FIG. 17A and FIG. 17B, the step device 41 of the embodiment includes stoppers 120 that restrict the movable range of the movable step 42 by coming into contact with the support arms 44. In particular, the step device 41 of the embodiment includes, as the stoppers 120, a first stopper 121 provided on the front bracket 45 f and a second stopper 122 provided on the rear bracket 45 r. The first stopper 121 restricts turning of the front main arm 81 f by coming into contact with the front main arm 81 f when the movable step 42 moves toward the inner side in the vehicle width direction and reaches the retracted position P1. The second stopper 122 restricts turning of the rear main arm 81 r by coming into contact with the rear main arm 81 r when the movable step 42 moves toward the outer side in the vehicle width direction and reaches the deployed position P2. By thus restricting the movable range of the movable step 42, the step device 41 of the embodiment prevents the chevron-like bent shape of the sub-arm 82 from becoming inverted.

Protective Cover

Next, the configuration of a protective cover provided in the step device 41 of the embodiment will be described.

As shown in FIG. 6 and FIG. 27 to FIG. 30 , the step device 41 of the embodiment includes a cover member 130 that is fixed to the lower surface 2 b of the vehicle body 2 so as to cover lower sides of the support arms 44.

Specifically, the cover member 130 of the embodiment includes a bottom wall 131 that is disposed under the support arms 44 and a peripheral wall 132 that is erected at edges of the bottom wall 131 so as to extend upward toward the lower surface 2 b of the vehicle body 2. In the cover member 130 of the embodiment, the bottom wall 131 is formed to be large enough to cover the lower sides of support arms 44 when the movable step 42 is in the retracted position P1. The peripheral wall 132 is erected at the edges of the bottom wall 131 so as to extend on the vehicle front side, the inner side in the vehicle width direction, and the vehicle rear side of the cover member 130. Thus, the cover member 130 of the embodiment forms a housing space 133 opening toward the outer side in the vehicle width direction, at a lower level than the lower surface 2 b of the vehicle body 2.

In particular, the cover member 130 of the embodiment is fastened along with the support brackets 45 of the support arms 44 to the lower surface 2 b of the vehicle body 2 by means of fastening portions 134 that are integrally formed in the peripheral wall 132. In the vehicle 1 of the embodiment, the cover member 130 forms the housing space 133 together with the lower surface 2 b of the vehicle body 2 and the lower surface 43 b of the sub-step 43, both located above the cover member 130. Thus, in the step device 41 of the embodiment, when the movable step 42 is in the retracted position P1, the substantially entire movable step 42 is housed along with the support arms 44 inside the housing space 133 formed by the cover member 130.

More specifically, as shown in FIG. 27 to FIG. 30 , the cover member 130 of the embodiment includes a seal member 135 that is interposed between the peripheral wall 132 and the vehicle body 2. In particular, the seal member 135 of the embodiment has a string-like outer shape with a substantially quadrangular cross-section. In the cover member 130 of the embodiment, the seal member 135 having such an outer shape is divided into parts and fixed to a leading end of the peripheral wall 132 erected at the edges of the bottom wall 131.

In particular, as shown in FIG. 31 and FIG. 32 , the cover member 130 of the embodiment has a plurality of notches 132 x that is provided in a peripheral wall part 132 i on the inner side in the vehicle width direction to avoid interference with the support brackets 45 of the support arms 44. In the cover member 130 of the embodiment, the seal member 135 is provided also at the notches 132 x along the edge of the bottom wall 131 continuously from the peripheral wall part 132 i by having its string-like shape bent into a substantially square-U-shape. Thus, as shown in FIG. 27 and FIG. 30 , in the cover member 130 of the embodiment, the seal member 135 is interposed also between the support bracket 45 and the peripheral wall part 132 i.

As shown in FIG. 33 , in the cover member 130 of the embodiment, the seal member 135 is provided also at a corner between the peripheral wall part 132 i on the inner side in the vehicle width direction and a peripheral wall part 132 f on the vehicle front side along the edge of the bottom wall 131 by having its string-like shape bent into a substantially L-shape. Thus, in the step device 41 of the embodiment, foreign objects, such as dust or mud water, are kept from entering the housing space 133 formed by the cover member 130 through a gap between the peripheral wall 132 of the cover member 130 and the lower surface 2 b of the vehicle body 2.

As shown in FIG. 33 and FIG. 34 , in the cover member 130 of the embodiment, a sloping surface 140 that slopes downward while extending from the vehicle front side toward the vehicle rear side is provided at the vehicle front-side peripheral wall part 132 f that is provided at a front end portion 130 f of the cover member 130. The long dashed double-short dashed line in FIG. 34 indicates the shape of the sloping surface 140 at a part where the fastening portion 134 is not provided. Based on the shape of the sloping surface 140, the cover member 130 of the embodiment mitigates the impact of foreign objects that, while the vehicle is running, collide from the vehicle front side with the peripheral wall part 132 f provided at the front end portion 130 f, such as small stones kicked up by a tire of the vehicle 1.

In the vehicle 1 of the embodiment, when the movable step 42 is in the retracted position P1, an opening 141 of the housing space 133 facing the outer side in the vehicle width direction is closed with a decorative member 142 (see FIG. 6 ) provided at a lower end of the sliding door 4. Thus, the step device 41 of the embodiment prevents foreign objects from entering the housing space 133 through the open part on the outer side in the vehicle width direction while the vehicle 1 is running.

As shown in FIG. 28 , the cover member 130 of the embodiment includes a fitting member 144 that is fitted into a window 143 provided in the peripheral wall part 132 i on the inner side in the vehicle width direction and thereby integrated with the peripheral wall part 132 i in a state of closing the window 143. In the step device 41 of the embodiment, the fitting member 144 can be removed to maintain the support arms 44 disposed inside the housing space 133 through the window 143.

Further, as shown in FIG. 6 , FIG. 21 , FIG. 27 , and FIG. 30 , the step device 41 of the embodiment includes a seal member 145 that is interposed between the bracket main body 85 and the holding member 86 composing the support bracket 45 of each support arm 44. In particular, in the step device 41 of the embodiment, the seal member 145 has a string-like outer shape with a substantially quadrangular cross-section, like the seal member 135 interposed between the peripheral wall 132 of the cover member 130 and the lower surface 2 b of the vehicle body 2. In the step device 41 of the embodiment, the seal member 145 is disposed so as to surround the base end part 44 b of each support arm 44 held between the bracket main body 85 and the holding member 86 such that foreign objects are kept from entering the first pivot-joint point M1 of the support arm 44 relative to the support bracket 45.

As shown in FIG. 6 , in the step device 41 of the embodiment, the cover member 130 is disposed at a higher level than a lower end 150 b of a rocker flange 150 that is provided on the lower surface 2 b of the vehicle body 2. Thus, in the step device 41 of the embodiment, the cover member 130 does not get in the way of lifting up the vehicle 1 using the rocker flange 150.

Coupling Structure of Guide Roller Unit

Next, the structure of coupling the guide roller unit 52 to the guide rail 50 in the step device 41 of the embodiment will be described.

As shown in FIG. 10 , FIG. 35A, and FIG. 35B, the guide roller unit 52 as a coupling member in the step device 41 of the embodiment has a structure in which the fixed member 61 that is fixed to the sliding door 4 and the arm member 62 that supports, at a leading end thereof, the guide roller 60 as the engaging part engaged with the guide rail 50 are turnably coupled together through a shaft member 160.

In particular, in the guide roller unit 52 of the embodiment, the fixed member 61 includes a main body 161 that is fixed to the sliding door 4 in a state of extending in the up-down direction, and a pair of opposite walls 163 that are provided at a lower end portion of the main body 161 and face each other. The arm member 62 includes a main body 164 that has a substantially flat-plate-like outer shape, and a pair of opposite walls 166 that are provided on a base end side of the main body 164 and face each other. In the guide roller unit 52 of the embodiment, the opposite walls 163 on the side of the fixed member 61 and the opposite walls 166 on the side of the arm member 62 have insertion holes 167, 168, respectively, formed at such positions as to face each other. In the guide roller unit 52 of the embodiment, the fixed member 61 and the arm member 62 are turnably coupled together as the shaft member 160 is inserted into the insertion holes 167, 168.

The guide roller unit 52 of the embodiment is provided with a helical torsion spring 170 that is interposed between the fixed member 61 and the arm member 62, with the shaft member 160 inserted in the helical torsion spring 170. In the guide roller unit 52 of the embodiment, based on an elastic force of the helical torsion spring 170 as an urging member, an urging force in the direction of lifting upward the guide roller 60 supported at the leading end of the arm member 62 is applied to the arm member 62 in a state where the fixed member 61 is fixed to the sliding door 4.

As shown in FIG. 35A, when the guide roller unit 52 of the embodiment is in a state of being coupled to the guide rail 50 provided on the movable step 42, the guide roller 60 is supported inside the guide rail 50 with a leading end side of the arm member 62 lifted upward based on the urging force of the helical torsion spring 170.

As shown in FIG. 35B, when the guide roller unit 52 of the embodiment is in an uncoupled state where the guide roller 60 is separated from the guide rail 50, the arm member 62 turns further such that the leading end side thereof supporting the guide roller 60 comes closer to the main body 161 of the fixed member 61 based on the urging force of the helical torsion spring 170. Thus, in the step device 41 of the embodiment, the guide roller unit 52 can be compactly folded, so that work efficiency in the uncoupled state is increased and, at the same time, the guide roller unit 52 does not get in the way of an occupant using the sliding door 4.

As shown in FIG. 10 , FIG. 35A, and FIG. 35B, the guide roller unit 52 of the embodiment has a stopper 171 that is integrally provided on the opposite wall 166 a of the arm member 62. When the guide roller unit 52 is in the uncoupled state, the stopper 171 comes into contact with the main body 161 of the fixed member 61 as the arm member 62 turns based on the urging force of the helical torsion spring 170. Thus, in the guide roller unit 52 of the embodiment, the amount of turning of the arm member 62 is restricted such that the arm member 62 urged by the helical torsion spring 170 and the guide roller 60 supported by the arm member 62 do not interfere with the sliding door 4.

As shown in FIG. 7 , FIG. 8 , FIG. 18 , and FIG. 36 , the guide rail 50 of the embodiment has notches 180 formed by cutting out portions of the fall prevention flange 59 provided at the lower end of the side wall 58. In the step device 41 of the embodiment, the notches 180 can be used to insert and remove the guide roller 60 of the guide roller unit 52 supported by the sliding door 4 into and from the guide rail 50 provided on the lower surface 42 b of the movable step 42.

As shown in FIG. 36 , at longitudinal positions at which the notches 180 are provided, the guide rail 50 of the embodiment allows the guide roller 60 to move in the up-down direction beyond the fall prevention flange 59 provided at the lower end of the side wall 58. Further, in the guide roller unit 52 of the embodiment, the arm member 62 can be pressed downward so as to turn against the urging force of the helical torsion spring 170. In the guide roller unit 52 of the embodiment, meanwhile, a stopper 172 (see FIG. 10 ) integrally provided on the opposite wall 166 a of the arm member 62 comes into contact with the main body 161 of the fixed member 61 and thereby restricts the amount of turning of the arm member 62 in the downward pressing direction. In the guide roller unit 52 of the embodiment, when this downward pressing force is removed, the arm member 62 can be turned again based on the urging force of the helical torsion spring 170.

Thus, in the step device 41 of the embodiment, the notches 180 provided in the guide rail 50 can be used to insert the guide roller 60 provided at the leading end of the arm member 62 into the guide rail 50 from below by turning the arm member 62 based on the urging force of the helical torsion spring 170. Moreover, the guide roller 60 supported inside the guide rail 50 can be separated downward from the guide rail 50 by turning the arm member 62 against the urging force of the helical torsion spring 170. Thus, in the step device 41 of the embodiment, the sliding door 4 supporting the guide roller unit 52 and the movable step 42 provided with the guide rail 50 can be easily coupled and uncoupled to and from each other.

Specifically, as shown in FIG. 7 , FIG. 8 , FIG. 18 , and FIG. 37 , the guide rail 50 of the embodiment includes a notch 181 provided at a longitudinal end portion 50 r on the vehicle rear side where the guide roller 60 is located when the sliding door 4 is fully opened. Thus, in the step device 41 of the embodiment, the sliding door 4 and the movable step 42 can be coupled and uncoupled to and from each other in a state where a sufficient working space is easy to secure owing to the movable step 42 being disposed in the deployed position P2 on the outer side in the vehicle width direction and the sliding door 4 being fully opened.

As shown in FIG. 7 , FIG. 8 , FIG. 18 , and FIG. 38 , the guide rail 50 of the embodiment has a notch 182 provided at a longitudinal position on the vehicle front side relative to the notch 181. In particular, the notch 182 is formed at a corner 70 c provided farthest on the vehicle rear side in the curved portion 70 that is provided at the longitudinal end portion 50 f on the vehicle front side. Thus, in the step device 41 of the embodiment, also when the sliding door 4 is located near the fully closed position Pc, the sliding door 4 and the movable step 42 can be coupled and uncoupled to and from each other in a state where a working space is easy to secure owing to the sliding door 4 having shifted toward the outer side in the vehicle width direction by opening and the movable step 42 having moved toward the outer side in the vehicle width direction.

The step device 41 of the embodiment includes a retaining member 190 that retains the movable step 42 in the retracted position P1 on the inner side in the vehicle width direction when the guide roller 60 is separated from the guide rail 50, i.e., the sliding door 4 and the movable step 42 are uncoupled from each other.

As shown in FIG. 28 , FIG. 29A, FIG. 29B, and FIG. 33 , in the step device 41 of the embodiment, the retaining member 190 is provided on the cover member 130 forming the housing space 133 when the movable step 42 is in the retracted position P1. In particular, the retaining member 190 of the embodiment is provided on the bottom wall 131, near the front end portion 130 f of the cover member 130. The retaining member 190 has a hook-shaped engaging projection 191. The retaining member 190 of the embodiment retains the movable step 42 in the retracted position P1 by having the engaging projection 191 engaged with the movable step 42.

Specifically, as shown in FIG. 39A and FIG. 39B, the retaining member 190 of the embodiment is turnably coupled to the bottom wall 131 of the cover member 130. In the step device 41 of the embodiment, turning the cover member 130 around a support shaft 190 x can switch between a used state where the engaging projection 191 does not engage with the movable step 42 and a retained state where the engaging projection 191 engages with the movable step 42 disposed in the retracted position P1.

In particular, as shown in FIG. 39A, in the used state where the movable step 42 is moved in the vehicle width direction in conjunction with the sliding door 4, the retaining member 190 of the embodiment is kept in a state where the engaging projection 191 faces the outer side in the vehicle width direction. Thus, in the step device 41 of the embodiment, the engaging projection 191 of the retaining member 190 does not interfere with the movable step 42 that moves in the vehicle width direction.

As shown in FIG. 39B, in the step device 41 of the embodiment, when the movable step 42 uncoupled from the sliding door 4 is to be retained in the retracted position P1, the retaining member 190 is turned in a counterclockwise direction in FIG. 39A and FIG. 39B, so that the engaging projection 191 faces the vehicle rear side where the movable step 42 is disposed. In the step device 41 of the embodiment, as the retaining member 190 thus turns, the engaging projection 191 is inserted into an engaging recess 192 provided at a front end portion 42 f of the movable step 42.

In the step device 41 of the embodiment, the engaging projection 191 of the retaining member 190 inserted into the engaging recess 192 of the movable step 42 is disposed inside the guide rail 50 at the longitudinal end portion 50 f on the vehicle front side. Thus, the step device 41 of the embodiment can retain the movable step 42 in the retracted position P1 as the retaining member 190 engages with the movable step 42.

Next, effects of the embodiment will be described. (1) The step device 41 includes the movable step 42 that is supported under the door opening 3, and the guide roller unit 52 as the coupling member that, in the state of being supported by the sliding door 4, engages with the movable step 42 to move the movable step 42 in the vehicle width direction in conjunction with opening and closing of the sliding door 4. The movable step 42 is provided with the guide rail 50 extending in the vehicle front-rear direction, with the guide roller 60 as the engaging part provided in the guide roller unit 52 that moves integrally with the sliding door 4 being disposed inside the guide rail 50. The guide roller unit 52 causes the movable step 42 to move from the retracted position P1 to the deployed position P2 as the guide roller 60 comes into sliding contact with the side wall 57 of the guide rail 50 that is located on the outer side in the vehicle width direction and, while pressing the side wall 57, moves inside the guide rail 50 in the direction of opening the sliding door 4. Further, the guide roller unit 52 causes the movable step 42 to move from the deployed position P2 to the retracted position P1 as the guide roller 60 comes into sliding contact with the side wall 58 of the guide rail 50 that is located on the inner side in the vehicle width direction and, while pressing the side wall 58, moves inside the guide rail 50 in the direction of closing the sliding door 4. The guide rail 50 is configured such that the terminal end region Lc on the closing side including the terminal end position Xc at which the guide roller 60 is located when the sliding door 4 is fully closed constitutes the closing-side free running zone αc in which the guide roller 60 does not press either of the side walls 57, 58.

The sliding door 4 has the width-direction shifting zone Rc near the fully closed position Pc. Opening the sliding door 4 from the fully closed position Pc requires a large force to move the sliding door 4 that is in a stationary state, and fully closing the sliding door 4 requires a force that allows the sliding door 4 to squeeze a seal member, such as a weatherstrip. Therefore, an increase in the force required to open and close the sliding door 4 caused by a load put on the sliding door 4 by the movable step 42 coupled thereto tends to be noticeable near the fully closed position Pc.

In the above configuration, however, the movable step 42 does not put a load on the sliding door 4 while the guide roller 60 moves through the terminal end region Lc on the closing side as the closing-side free running zone αc set in the guide rail 50. Thus, the force required to open and close the sliding door 4 can be reduced.

(2) The closing-side free running zone αc constitutes the non-sliding-contact zone γ in which the guide roller 60 that moves inside the guide rail 50 in the vehicle front-rear direction moves in the vehicle width direction while shifting in the rail width direction of the guide rail 50 without coming into sliding contact with either of the side walls 57, 58.

The guide roller 60 of the guide roller unit 52 does not come into sliding contact with either of the side walls 57, 58 of the guide rail 50, so that the free running zone for the guide roller 60 can be formed more reliably. Thus, the force required to open and close the sliding door 4 can be reduced more effectively.

(3) In the non-sliding-contact zone γ, the gradient of change θ1 of the side wall 57 located on the outer side of the guide roller 60 in the vehicle width direction is set to be smaller than the gradient of change θr set for the track of movement Qr of the guide roller 60 that moves inside the guide rail 50 in the vehicle front-rear direction while moving in the vehicle width direction.

In this configuration, when the sliding door 4 opens, the guide roller 60 that moves inside the guide rail 50 toward the vehicle rear side shifts in the rail width direction so as to be gradually closer to the side wall 57 located on the outer side of the guide roller 60 in the vehicle width direction. Thus, the guide roller 60 having passed through the closing-side free running zone αc comes quickly into sliding contact with the side wall 57 located on the outer side of the guide roller 60 in the vehicle width direction and presses the side wall 57. In this way, the movable step 42 can be smoothly moved from the retracted position P1 toward the deployed position P2.

(4) In the non-sliding-contact zone 7, the gradient of change θ2 of the side wall 58 located on the inner side of the guide roller 60 in the vehicle width direction is set to be larger than the gradient of change θr set for the track of movement Qr of the guide roller 60 that moves inside the guide rail 50 in the vehicle front-rear direction while moving in the vehicle width direction.

In this configuration, when the sliding door 4 closes, the guide roller 60 that moves inside the guide rail 50 toward the vehicle front side shifts in the rail width direction so as to be gradually away from the side wall 58 located on the inner side of the guide roller 60 in the vehicle width direction. Thus, the guide roller 60 having entered the closing-side free running zone αc is quickly separated from the side wall 58 located on the inner side of the guide roller 60 in the vehicle width direction. In this way, the movable step 42 can be smoothly stopped upon reaching the retracted position P1.

(5) The guide rail 50 is configured such that the moving region Lo on the opening side from the moving position X2 at which the guide roller 60 is located when the movable step 42 reaches the deployed position P2 constitutes the opening-side free running zone αo in which the guide roller 60 does not press either of the side walls 57, 58.

An occupant of the vehicle may place his or her foot on the movable step 42 even if the sliding door 4 is still opening or closing. As a result, the movable step 42 coupled to the sliding door 4 may put a large load thereon.

In the above configuration, however, the movable step 42 does not put a load on the sliding door 4 while the guide roller 60 moves through the opening-side moving region Lo as the opening-side free running zone αo set in the guide rail 50. Thus, the force required to open and close the sliding door 4 can be reduced.

(6) The opening-side free running zone αo constitutes the parallel zone ε in which the side walls 57, 58 of the guide rail 50 extend parallel to the track of movement Qr of the guide roller 60. The sliding door 4 has the width-direction shifting zone Rc near the fully closed position Pc. When shift of the sliding door 4 toward the outer side in the vehicle width direction is completed during opening of the sliding door 4, the guide roller 60 that moves integrally with the sliding door 4 moves in the vehicle front-rear direction in a substantially straight line. In the above configuration, therefore, the opening-side moving region Lo can be easily set as the opening-side free running zone αo in a simple configuration.

(7) The side wall 57 of the guide rail 50 on the outer side in the vehicle width direction is formed by the peripheral wall 55 of the movable base 47 constituting the lower surface 42 b of the movable step 42, and the side wall 58 of the guide rail 50 on the inner side in the vehicle width direction is formed by the rail members 53, 54 facing the peripheral wall 55 in the vehicle width direction.

Thus forming the side walls 57, 58 using wall members that are independent of and different from each other allows greater flexibility in designing the guide rail 50. Thus, a free running zone for the guide roller 60 can be more easily set in the guide rail 50.

(8) The sliding door 4 is provided with the catching detection device 32 that detects whether any object is caught in the sliding door based on a change in the force required to open and close the sliding door 4. In the case of the sliding door 4 that is provided with the catching detection device 32, a load put on the sliding door 4 by the movable step 42 coupled thereto may cause errors in catching detection of the catching detection device 32. For such a sliding door 4, employing the configurations (1) to (7) can reduce the likelihood of errors in catching detection.

The above embodiment can be implemented with changes made thereto as follows. The embodiment and the following modified examples can be implemented in combination within such a range that no technical inconsistency arises.

-   -   In the above embodiment, the present disclosure is implemented         as the step device 41 that operates in conjunction with the         rearward opening sliding door 4 that opens toward the vehicle         rear side. However, the present disclosure may instead be         applied to a frontward opening sliding door 4 that opens toward         the vehicle front side.     -   In the above embodiment, the sliding door 4 is opened and closed         by being driven by the power sliding door device 31. However,         the present disclosure may instead be applied to a sliding door         4 that does not have such a power sliding door device 31.     -   In the above embodiment, the power sliding door device 31         functions as the catching detection device 32 that detects         whether any object is caught in the sliding door 4 based on         changes in the force required to open and close the sliding door         4. As one example of this detection, the power sliding door         device 31 determines that an object is caught in the sliding         door 4 when the amount of current to the motor 31 m increases         beyond a predetermined threshold value while the sliding door 4         is driven to open or close. However, the present disclosure is         not limited to this example, and detection of whether any object         is caught in the sliding door 4 may instead be based on changes         in rotation of the motor 31 m. Further, the present disclosure         may be applied to a sliding door 4 provided with a catching         detection device 32 independent of the power sliding door device         31, as long as the catching detection device 32 executes         detection of whether any object is caught in the sliding door 4         based on changes in the force required to open or close the         sliding door 4. In addition, the present disclosure may be         applied to a sliding door 4 that is not provided with such a         catching detection device 32.     -   In the above embodiment, the movable step 42 moves in the         vehicle width direction while maintaining the substantially         horizontal posture. However, the posture need not be necessarily         horizontal and may instead be, for example, inclined downward         toward the outer side in the vehicle width direction.     -   In the above embodiment, in the guide rail 50, the peripheral         wall 55 of the movable base 47 constituting the lower surface 42         b of the movable step 42 forms the side wall 57 on the outer         side in the vehicle width direction, and the rail members 53, 54         facing the peripheral wall 55 in the vehicle width direction         form the side wall 58 on the inner side in the vehicle width         direction. However, an applicable embodiment of the present         disclosure is not limited to this example, and two independent         wall members formed as parts separate from the movable step 42         may be fixed to the lower surface 42 b of the movable step 42 to         form the side walls 57, 58 of the guide rail 50. Alternatively,         for example, a rail member with a substantially square-U-shaped         cross-section opening downward may be fixed to the lower surface         42 b of the movable step 42 to form the guide rail 50. In         addition, the guide rail 50 may be integrally formed in the         movable step 42.     -   In the above embodiment, the closing-side free running zone αc         constitutes the non-sliding-contact zone γ in which the guide         roller 60 moving inside the guide rail 50 in the vehicle         front-rear direction moves in the vehicle width direction while         shifting in the rail width direction of the guide rail 50         without coming into sliding contact with the side walls 57, 58.         The opening-side free running zone αo constitutes the parallel         zone ε in which the side walls 57, 58 of the guide rail 50         extend parallel to the track of movement Qr of the guide roller         60. However, an applicable embodiment of the present disclosure         is not limited to this example, and the closing-side free         running zone αc may constitute the parallel zone ε The         opening-side free running zone αo may constitute the         non-sliding-contact zone γ.     -   In the above embodiment, in the non-sliding-contact zone γ, the         Gradient of change θ1 of the side wall 57 on the outer side in         the vehicle width direction is set to be smaller than the         gradient of change θr set for the track of movement Qr of the         guide roller 60, and the gradient of change θ2 of the side wall         58 on the inner side in the vehicle width direction is set to be         larger than the gradient of change θr. However, an applicable         embodiment of the present disclosure is not limited to this         example, and for example, simply a larger rail width may be set,         as long as the guide roller 60 moving inside the guide rail 50         in the vehicle front-rear direction can move in the vehicle         width direction while shifting in the rail width direction of         the guide rail 50 without coming into sliding contact with the         side walls 57, 58.     -   In the above embodiment, during opening of the sliding door 4,         the movable step 42 reaches the deployed position P2 at the same         time as shift of the sliding door 4 toward the outer side in the         vehicle width direction is completed. However, an applicable         embodiment of the present disclosure is not limited to this         example, and as shown in FIG. 40 , during opening of the sliding         door 4, the movable step 42 may reach the deployed position P2         before shift of the sliding door 4 toward the outer side in the         vehicle width direction is completed.

An occupant of the vehicle 1 may start to get in or out of the vehicle 1 when shift of the sliding door 4 toward the outer side in the vehicle width direction is completed, even if the sliding door 4 is still opening. In the above configuration, the movable step 42 has already reached the deployed position P2 by that time. This can reduce the likelihood that an occupant may place his or her foot on the movable step 42 that is moving outward in the vehicle width direction.

Further, the moving position X3 at which the guide roller 60 is located when shift of the sliding door 4 toward the outer side in the vehicle width direction is completed is already in the opening-side moving region Lo, i.e., the opening-side free running zone αo set for the guide rail. Thus, even when an occupant of the vehicle 1 places his or her foot on the movable step 42 before shift of the sliding door 4 toward the outer side in the vehicle width direction is completed, the movable step 42 is less likely to put a load on the sliding door 4.

-   -   In the above embodiment, the sub-step 43 is formed by turnably         coupling the step part 72 forming the step surface S2 to the         base part 71 that is fixed to the vehicle body 2. However, an         applicable embodiment of the present disclosure is not limited         to this example, and the base part 71 and the step part 72 may         be fixed to each other in a substantially L-shape.     -   In the above embodiment, the base part 71 and the step part 72         of the sub-step 43 are formed by laying the resin covers 77, 78         on the base members 75, 76, but instead both or one of the base         part 71 and the step part 72 may be composed of a single part.         Alternatively, the base part 71 and the step part 72 may be         integrally formed.     -   In the above embodiment, in the sub-step 43, the projection 79         provided on the resin cover 78 so as to protrude toward the side         of the lower surface 72 b comes into sliding contact with the         upper surface 42 a of the movable step 42 at the leading end         portion of the step part 72. However, an applicable embodiment         of the present disclosure is not limited to this example, and         the portion at which the step part 72 of the sub-step 43 comes         into sliding contact with the upper surface 42 a of the movable         step 42 need not be necessarily the leading end portion and may         instead be a portion on the base end side.     -   The step part 72 of the sub-step 43 and the upper surface 42 a         of the movable step 42 need not necessarily directly come into         sliding contact with each other, and may instead, for example,         come into sliding contact with each other through an attached         part having elasticity, such as a brush or a lip seal.         Alternatively, a gap may be left between the lower surface 72 b         of the step part 72 on the side of the sub-step 43 and the upper         surface 42 a of the movable step 42, without these surfaces         coming into sliding contact with each other.     -   As in a step device 41B shown in FIG. 41 , movement of a movable         step 42B toward the outer side in the vehicle width direction         may be restricted as a first engaging part 201 provided on the         movable step 42B and a second engaging part 202 provided on a         sub-step 43B engage with each other when the movable step 42B         moves to the deployed position P2.

For example, in the step device 41B, an engaging projection 205 protruding toward the upper side of the movable step 42B is provided at a base end portion 203 of the movable step 42B. An engaging projection 208 protruding toward the lower side of a step part 72B of the sub-step 43B is provided at a leading end portion 206 of the step part 72B. In the step device 41B, the engaging projection 205 engages with the engaging projection 208 on the side of the sub-step 43B when the movable step 42B moves toward the outer side in the vehicle width direction and reaches the deployed position P2. In the step device 41B, the engaging projections 205, 208 serve as the first engaging part 201 and the second engaging part 202 to restrict movement of the movable step 42B toward the outer side in the vehicle width direction.

This configuration can maintain a constant positional relationship between the movable step 42B and the sub-step 43B when the movable step 42B is in the deployed position P2. This makes it possible to further enhance the unity of the step surface S1 of the movable step 42 and the step surface S2 of the sub-step 43 by, for example, connecting the step surfaces S1, S2 of the movable step 42 and the sub-step 43 to each other so as to obscure the border between the decorative shapes thereof.

The shapes of the first engaging part 201 and the second engaging part 202 may be arbitrarily changed. For example, one of the first engaging part 201 and the second engaging part 202 may have a recessed shape. Further, the position at which the first engaging part 201 is formed need not necessarily be the base end portion 203 of the movable step 42B. The position at which the second engaging part 202 is formed need not necessarily be the leading end portion 206 of the step part 72B, either.

-   -   In the above embodiment, the pressure bearing members 100 are         made of a resin having a shock absorbing property and a         self-lubricating property. However, the material of the pressure         bearing members 100 may be arbitrarily changed. As long as the         pressure bearing members 100 can come into sliding contact with         the support arms 44 and bear the load thereof, the pressure         bearing member 101 provided on the support bracket 45 and the         pressure bearing member 111 on the side of the movable step 42         provided on the holding member 110 may be made of different         materials. For example, one of the pressure bearing members 101,         111 may be made of resin and the other may be made of metal. The         possibility of forming both the pressure bearing members 101,         111 using other materials than resin is not eliminated.     -   The shape of the pressure bearing members 100 may be arbitrarily         changed. For example, the pressure bearing member 111 on the         side of the movable step 42 may have a form of a substantially         arc-shaped flat plate, like the pressure bearing member 101 on         the side of the support bracket 45. Further, at least one of the         pressure bearing members 101, 111 may form a sliding surface of         other shape than an arc shape that extends in a direction         intersecting the support arm 44. The pressure bearing member 101         on the side of the support bracket 45 may have a form of a         substantially rectangular flat plate, like the pressure bearing         member 111 on the side of the movable step 42.     -   The number and arrangement of the pressure bearing members 100         may also be arbitrarily changed. For example, only one of the         pressure bearing member 101 on the side of the support bracket         45 and the pressure bearing member 111 on the side of the         movable step 42 may be provided. In the above embodiment, only         the main arms 81 are each provided with the holding member 110         and the pressure bearing member 111. However, the sub-arm 82 may         also be provided with a similar holding member 110 and pressure         bearing member 111. Further, only the sub-arm 82, or the sub-arm         82 and one of the main arms 81 may be provided with the holding         member 110 and the pressure bearing member 111. In the above         embodiment, all the support arms 44 are provided with the         pressure bearing member 101 on the side of the support bracket         45. However, the pressure bearing member 101 on the side of the         support bracket 45 may be selectively provided; for example,         only the main arms 81 may be each provided with the pressure         bearing member 101 on the support bracket 45.     -   In the above embodiment, the ridges 118 provided on the lower         surface 48 b of the resin cover 48 protrude toward the lower         surface 42 b of the movable step 42 through the holes 119         provided in the movable base 47. However, an applicable         embodiment of the present disclosure is not limited to this         example, and the structure and material of the ridges 118 may be         arbitrarily changed. For example, the ridges 118 may be made of         metal. The ridges 118 may be provided on the member forming the         lower surface 42 b of the movable step 42.     -   In the above embodiment, the step device 41 includes, as the         support arms 44, two main arms 81 and one sub-arm 82 provided         between the main arms 81. However, an applicable embodiment of         the present disclosure is not limited to this example, and the         number and arrangement of the sub-arm 82 may be arbitrarily         changed. For example, two or more sub-arms 82 may be provided. A         sub-arm 82 may be provided on the vehicle front side or the         vehicle rear side of the main arms 81. Alternatively, the         sub-arm 82 may be omitted and the movable step 42 may be         supported by two main arms 81.     -   A configuration may be adopted in which the support arms 44 that         are turnably coupled to both the vehicle body 2 and the movable         step 42 are used in combination with other support structure,         for example, a rail-and-slider.     -   In the above embodiment, the step device 41 includes, as the         stoppers 120, the first stopper 121 that restricts turning of         the front main arm 81 f by coming into contact with the front         main arm 81 f when the movable step 42 reaches the retracted         position P1, and the second stopper 122 that restricts turning         of the rear main arm 81 r by coming into contact with the rear         main arm 81 r when the movable step 42 reaches the deployed         position P2. However, an applicable embodiment of the present         disclosure is not limited to this example, and the configuration         and arrangement of the stoppers 120 may be arbitrarily changed         as long as the stoppers 120 restrict the movable range of the         movable step 42 by coming into contact with the support arms 44.     -   The material of the cover member 130 may be arbitrarily changed.         The material may be resin or metal.—In the above embodiment, the         cover member 130 includes the bottom wall 131 that is disposed         under the support arms 44 and the peripheral wall 132 that is         provided at the edges of the bottom wall 131. However, the shape         of the cover member 130 may be arbitrarily changed. For example,         the cover member 130 may have a dome shape or the like in which         there is no distinction between the bottom wall 131 and the         peripheral wall 132. The seal member 135 interposed between the         vehicle body 2 and the peripheral wall 132 may be omitted. The         possibility of leaving a gap between the cover member 130 and         the lower surface 2 b of the vehicle body 2 is not eliminated.     -   In the above embodiment, the cover member 130 forms the housing         space 133 together with the lower surface 2 b of the vehicle         body 2 and the lower surface 43 b of the sub-step 43.         Alternatively, the cover member 130 may form the housing space         133 together with only the lower surface 2 b of the vehicle body         2.     -   In the state where the movable step 42 is in the retracted         position P1, at least part of the step surface S1 may be exposed         toward the upper side. The lower surface 42 b of the movable         step 42 may be partially exposed toward the lower side of the         cover member 130.     -   In the above embodiment, the helical torsion spring 170 is used         as the urging member that applies an urging force in the         direction of lifting the guide roller 60 to the arm member 62.         However, other elastic member, such as an extension spring or a         compression spring, may be used as the urging member.     -   In the above embodiment, the guide rail 50 has, as the notches         180, the notch 181 provided at the longitudinal end portion 50 r         on the vehicle rear side and the notch 182 formed at the corner         70 c farthest on the vehicle rear side in the curved portion 70         provided at the longitudinal end portion 50 f on the vehicle         front side. However, an applicable embodiment of the present         disclosure is not limited to this example, and the number and         arrangement of the notches 180 may be arbitrarily changed. For         example, there may be only one notch 180 and that notch 180 may         be the notch 181 at the longitudinal end portion 50 r on the         vehicle rear side. Alternatively, three or more notches 180 may         be provided apart from one another in the longitudinal direction         of the guide rail 50.     -   In the above embodiment, the fall prevention flange 59 is         provided at the lower end portion of the side wall 58 on the         inner side in the vehicle width direction. However, the fall         prevention flange 59 may instead be provided at the lower end         portion of the side wall 57 on the outer side in the vehicle         width direction.     -   In the above embodiment, the retaining member 190 has the         hook-shaped engaging projection 191 and is coupled to the bottom         wall 131 of the cover member 130. Turning the retaining member         190 around the support shaft 190 x can switch between the used         state where the engaging projection 191 does not engage with the         movable step 42 and the retained state where the engaging         projection 191 engages with the movable step 42. However, an         applicable embodiment of the present disclosure is not limited         to this example, and the structure of retaining the movable step         42 by the retaining member 190 may be arbitrarily changed. The         position at which the retaining member 190 is disposed may also         be arbitrarily changed, for example, to the sub-step 43 or the         support bracket 45.

In the step device for a vehicle, the closing-side free running zone may be a non-sliding-contact zone in which the engaging part that moves inside the guide rail in the front-rear direction of the vehicle moves in the vehicle width direction while shifting in a rail width direction of the guide rail without coming into sliding contact with either of the side walls.

In this aspect, the engaging part of the coupling member does not come into sliding contact with either of the side walls of the guide rail, so that the free running zone for the engaging part can be formed more reliably. Thus, the force required to open and close the sliding door can be reduced more effectively.

In the step device for a vehicle, in the non-sliding-contact zone, a gradient of change of the side wall located on the outer side of the engaging part in the vehicle width direction may be set to be smaller than a gradient of change set for a track of movement of the engaging part that moves inside the guide rail in the front-rear direction of the vehicle while moving in the vehicle width direction.

In this aspect, when the sliding door opens, for example, the engaging part of the coupling member that moves inside the guide rail toward a vehicle rear side shifts in the rail width direction so as to be gradually closer to the side wall located on the outer side of the engaging part in the vehicle width direction. Thus, the engaging part of the coupling member having passed through the closing-side free running zone comes quickly into sliding contact with the side wall located on the outer side of the engaging part in the vehicle width direction and presses the side wall. In this way, the movable step can be smoothly moved from the retracted position toward the deployed position.

In the step device for a vehicle, in the non-sliding-contact zone, a gradient of change of the side wall located on the inner side of the engaging part in the vehicle width direction may be set to be larger than a gradient of change set for a track of movement of the engaging part that moves inside the guide rail in the front-rear direction of the vehicle while moving in the vehicle width direction.

In this aspect, when the sliding door closes, for example, the engaging part of the coupling member that moves inside the guide rail toward a vehicle front side shifts in the rail width direction so as to be gradually away from the side wall located on the inner side of the engaging part in the vehicle width direction. Thus, the engaging part of the coupling member having entered the closing-side free running zone is quickly separated from the side wall located on the inner side of the engaging part in the vehicle width direction. In this way, the movable step can be smoothly stopped upon reaching the retracted position.

In the step device for a vehicle, the guide rail may be configured such that a moving region on an opening side from a moving position at which the engaging part is located when the movable step reaches the deployed position constitutes an opening-side free running zone in which the engaging part does not press either of the side walls.

An occupant of the vehicle may place his or her foot on the movable step even if the sliding door is still opening or closing. As a result, the movable step coupled to the sliding door may put a large load thereon.

In the above aspect, however, the movable step does not put a load on the sliding door while the engaging part of the coupling member moves through the opening-side moving region as the opening-side free running zone set in the guide rail. Thus, the force required to open and close the sliding door can be reduced.

In the step device for a vehicle, the opening-side free running zone may be a parallel zone in which the side walls extend parallel to the track of movement of the engaging part. Typically, a sliding door has a shifting zone in a vehicle width direction near its fully closed position. In most cases, when shift of a sliding door toward an outer side in the vehicle width direction is completed during opening of the sliding door, the engaging part of the coupling member that moves integrally with the sliding door moves in the vehicle front-rear direction in a substantially straight line. In the above aspect, therefore, the moving region on the opening side can be easily set as the opening-side free running zone in a simple configuration.

In the step device for a vehicle, the movable step may be configured to reach the deployed position before shift of the sliding door toward the outer side in the vehicle width direction is completed during opening of the sliding door.

An occupant of the vehicle may start to get in or out of the vehicle when shift of the sliding door toward the outer side in the vehicle width direction is completed, even if the sliding door is still opening. In the above aspect, the movable step has already reached the deployed position by that time. This can reduce the likelihood that an occupant may place his or her foot on the movable step that is moving outward in the vehicle width direction.

Further, the moving position at which the engaging part of the coupling member is located when shift of the sliding door toward the outer side in the vehicle width direction is completed is already in the opening-side moving region, i.e., the opening-side free running zone set in the guide rail. This has an advantage in that, even when an occupant of the vehicle places his or her foot on the movable step before shift of the sliding door toward the outer side in the vehicle width direction is completed, the movable step hardly puts any load on the sliding door.

In the step device for a vehicle, the side walls of the guide rail facing each other in the vehicle width direction may be formed by wall members that are independent of and different from each other.

In this aspect, greater flexibility is allowed in designing the guide rail. Thus, a free running zone for the engaging part can be more easily set in the guide rail. In the step device for a vehicle, the sliding door may include a catching detection device that detects whether any object is caught in the sliding door based on a change in the force required to open and close the sliding door.

In the case of a sliding door that is provided with a catching detection device as in this aspect, a load put on the sliding door by the movable step coupled thereto may cause errors in catching detection of the catching detection device. For such a sliding door, providing the guide rail with a free running zone that can reduce the force required to open and close the sliding door can reduce the likelihood of errors in catching detection. 

What is claimed is:
 1. A step device for a vehicle, the step device comprising: a movable step that is supported under a door opening of the vehicle; and a coupling member that, in a state of being supported by a sliding door that moves in a front-rear direction of the vehicle with a shifting zone in a width direction of the vehicle, engages with the movable step to move the movable step in the vehicle width direction in conjunction with opening and closing of the sliding door, wherein: the movable step includes a guide rail extending in the front-rear direction of the vehicle, with an engaging part of the coupling member that moves integrally with the sliding door being disposed inside the guide rail; the coupling member is configured to cause the movable step to move from a retracted position to a deployed position as the engaging part comes into sliding contact with a side wall of the guide rail that is located on an outer side in the vehicle width direction and, while pressing the side wall, moves inside the guide rail in a direction of opening the sliding door; the coupling member is configured to cause the movable step to move from the deployed position to the retracted position as the engaging part comes into sliding contact with a side wall of the guide rail that is located on an inner side in the vehicle width direction and, while pressing the side wall, moves inside the guide rail in a direction of closing the sliding door; and the guide rail is configured such that a terminal end region on a closing side including a terminal end position at which the engaging part is located when the sliding door is fully closed constitutes a closing-side free running zone in which the engaging part does not press either of the side walls.
 2. The step device for a vehicle according to claim 1, wherein the closing-side free running zone is a non-sliding-contact zone in which the engaging part that moves inside the guide rail in the front-rear direction of the vehicle moves in the vehicle width direction while shifting in a rail width direction of the guide rail without coming into sliding contact with either of the side walls.
 3. The step device for a vehicle according to claim 2, wherein, in the non-sliding-contact zone, a gradient of change of the side wall located on the outer side of the engaging part in the vehicle width direction is set to be smaller than a gradient of change set for a track of movement of the engaging part that moves inside the guide rail in the front-rear direction of the vehicle while moving in the vehicle width direction.
 4. The step device for a vehicle according to claim 2, wherein, in the non-sliding-contact zone, a gradient of change of the side wall located on the inner side of the engaging part in the vehicle width direction is set to be larger than a gradient of change set for a track of movement of the engaging part that moves inside the guide rail in the front-rear direction of the vehicle while moving in the vehicle width direction.
 5. The step device for a vehicle according to claim 1, wherein the guide rail is configured such that a moving region on an opening side from a moving position at which the engaging part is located when the movable step reaches the deployed position constitutes an opening-side free running zone in which the engaging part does not press either of the side walls.
 6. The step device for a vehicle according to claim 5, wherein the opening-side free running zone is a parallel zone in which the side walls extend parallel to a track of movement of the engaging part.
 7. The step device for a vehicle according to claim 5, wherein the movable step is configured to reach the deployed position before shift of the sliding door toward the outer side in the vehicle width direction is completed during opening of the sliding door.
 8. The step device for a vehicle according to claim 1, wherein the side walls of the guide rail facing each other in the vehicle width direction are formed by wall members that are independent of and different from each other.
 9. The step device for a vehicle according to claim 1, wherein the sliding door includes a catching detection device that detects whether any object is caught in the sliding door based on a change in a force required to open and close the sliding door. 